Wijngaard test around inclusions in microstructured solid and hollow core optical fibers

In this paper we describe the electromagnetic proprieties of modes in microstructured optical fibers (MOFs). It is well known that optical fibers have a large number of modes that can be used in different types of structures, at certain wavelengths. Also, multi-structural optical fibers have remarkable properties, namely: variable dispersion, nonlinearity, and single-mode operation over a wide range of wavelengths. We investigated the propagation of the electromagnetic modes, at different wavelengths in two types of MOFs: solid core fibers and hollow core fibers. Wijngaard stated that in a certain region, a field can be written as a superposition of outgoing waves from all source bodies. To describe the stability of the effective refractive index we used the Wijngaard test around inclusions in MOFs, we computed the Wijngaard integral W, which is a measure of the accuracy of the equality between the local and the Wijngaard expansions. Our simulations were made in CUDOS MOF Utilities software and are based on the multipole mathematical method.